Pilot bearing



Oct. 21, 1947. l l J. G, JERGENS `2,429,516

PILOT BEARING Filed May 20, 1946 /z 36 35 zo Patented Oct. 21, 1947 UNITED STATES PATENT OFFICE PILOT BEARING John G. J ergens, Shaker Heights, Ohio Application May 20, 1946, Serial No. 670,859

(Cl. 30S-187.1)

4 Claims.

lThis invention relates to pilot bushings adapted to provide a bearing between elements having relatively rotary and axial movements, such as for example between rotating and non-rotating spindles of a lathe, or between a fixture and an axially movable shaft such as a drill spindle.

Objects of the invention are to provide a pilot bushing which is of simple construction and easy to assemble; to provide a pilot bushing that is easy to adjust to compensate for wear; to provide a pilot bushing capable of resisting heavy axial and radial thrusts, and to provide a bushing having improved lubricant retaining means.

It is also an object of the invention to provide a bushing that is so constructed that it can be readily mounted in a cylindrical bore formed in a spindle or fixture and which can be quickly and easily replaced with a bushing of` a different internal diameter.

With the above and other objects in View, the invention may be said to comprise the pilot bushing as illustrated in the accompanying drawings, hereinafter described and particularly set forth in the appended claims, together with such variations and modifications thereof as will be apparent to one skilled in the art to which the invention pertains.

Reference should be had to the accompanying drawings forming a part of this specication, in which:

Figure 1 is a sectional view showing a pilot bushing of the present invention mounted in the rotary spindle of a lathe and rotatable and slidable on a stationary spindle;

Fig. 2 is an axial section through the pilot bushing shown in Fig. 1;

Fig. 3 is a sectional View showing a pair of pilot bushings embodying the invention mounted in a work holding fixture to guide a vertically movable drill spindle, and

Fig. 4 is an axial section through the pilot bushing shown in Fig. 3.

Referring to Fig. l of the drawing, a pilot bushing A is mounted in an end of a tubular lathe spindle I which carries a work supporting holder or chuck 2. As herein illustrated, the holder 2 supports a hollow work piece 3 through which a stationary spindle 4 extends. The spindle 4 has one end slidably mounted in the bushing A and its opposite end rigidly secured to a tailstock 5 by suitable means such as a screw 6. The spindle I moves axialiy as it rotates and the spindle 4 has a cutting tool 'I mounted therein which engages the interior of the work piece 3 as the work piece is rotated and advanced axially.

In Fig. 3 of the drawing two pilot bushings B are shown mounted in a work holding fixture 8, the bushings B being axially alined and superposed one above the other. The bushings B provide bearings for a vertically movable rotating drill spindle ASi which carries a boring or reaming tool l0 for engagement in-teriorly of a work piece mounted in the fixture 8.

Referring to Fig. 2 of the drawing, the bushing A comprises an inner sleeve I I and an outer sleeve I2. The two sleeves are coaxial and the outer sleeve is of greater diameter and spaced radially from the inner sleeve to provide an annular bearing receiving chamber between the sleeves. The sleeve II has an external shoulder I3 adjacent one end and the sleeve I2 has an internal shoulder It adjacent one of its ends. The two sleeves are assembled with the shoulders I3 and I4 oppositely disposed'to position bearing races mounted on the two sleeves. The inner sleeve II is externally threaded at one end and receives a closure member l5 which is in the form of a collar screwed upon the sleeve I-I. The collar I5 is partially split `by means of` a circumferential slot I6 and is adapted to be locked in adjusted positions by means of `a spreading screw II that is threaded in an opening that extends from the outer edge oi the collar to the slot I6 substantially midway between the ends of the slot to spread apart the portions of the collar separated by the slot and frictionallylock the threads of the co1- lar and sleeve. The external sleeve I2 is internal- 1y threaded at the end opposite that provided with the shoulder I4 and an annular closure member I8 is screwed into the sleeve I2. The closure member I 8 is provided with spanner sockets I9 and has a shoulder 20 that engages the end of the sleeve I2. A bearing cup 2I is slidably mounted within the sleeve I2 and is clamped between the shoulder I4 and the inner end of the closure member I8. The bearing cup ZI has oppositely tapering cone surfaces 22 and a pair of cone rings 23 are mounted on the inner sleeve I I, one within each of the cone surfaces 22 of the cup. A spacer 24 is interposed between the cone rings 23 and cone rollers 25 mounted in suitable cages 26 are interposed betweenthe cone rings 23 and the conical surfaces 22 of the cup. The cone rings 23. and spacer 24 are clamped between the shoulder I3 of the inner sleeve II and the adjustable collar l5. The bearing can be readily adjusted to take up wear on the cup or cone rings by removing the bearing, grinding the spacer 24 to make it narrower, reassembling the bearing and tightly clamping the cone rings by adjusting the collar I5.

A lubricant retaining disc 21 is clamped between the shoulder I3 of the inner sleeve and the adjacent cone ring and a second lubricant retaining disc 28 is clamped between the collar I5 and the adjacent cone ring. The retaining discs 21 and 28 fit upon the exterior of the sleeve I I, the disc 21 having small clearance within the closure member I8 attached to the outer sleeve I2 and the disc 28 having small clearance within the interior of the sleeve II2 at the opposite end of the bushing.

The closure member I8 has an inner face 29 that is closely adjacent the disc 21 and the sleeve i2 has an integrally projecting iiange 30 that closely overlies the outer face of the disc 28. Because of the small clearance between the discs 21 and 128 and the relatively rotatable outer sleeve, the leakage of lubricant past the outer peripheries of the disc is greatly retarded and the narrow annular chambers exteriorly of the discs further retard the escape of lubricant since centrifugal force tends to hold the lubricant in the narrow annular spaces between the closure member I8 and flange 30 and the outer faces of the discs. Additional sealing means is preferably provided exteriorly of the retaining discs 21 and 28. As shown in Fig. 2, the closure member I8 is provided with a labyrinth seal 3I and a sealing ring 32 is mounted in the sleeve I2 and engages with the periphery of the collar I5.

A lubricant fitting 33 is attached in a socket 34 formed in the closure member I8 which communicates with a passage 35 formed in the sleeve I2 and extending to a central point where it cornmunicates with a radial passage 36 through the bearing cup 2|. Lubricant may be introduced through the tting 33 into the bearing chamber and lubricant so introduced may substantially iill the space between the retaining discs 21 and 28.

In assembling the bearing the disc 21 is slipped over the small end of the inner sleeve I I and positioned against the shoulder I3 after which the cone ring 23 that tapers toward the small end of the sleeve II withrits rollers 25 in place, is positioned against the inner face of the ring 21. The spacer ring 24 is then placed against the inner edge of the cone ring and the bearing cup is positioned in engagement with the rollers 25 on the previously positioned cone ring. The second the flange 40 and which is attached to the flange 48 by means of bolts 42. In this modication the closure member I8a is provided with a seal in the form of a packing ring 43 that is held in place by means of an angle shaped retaining ring 44 which has a flat ange forming an inner wall of the closure member corresponding to the inner wall 29 of the closure member I8 in the modification first described. Otherwise the bushing shown in Fig. 4 is substantially identical with that shown in Fig. 2.

It is to be understood that variations and modications of the specific devices herein shown and described for purposes oi illustration, may be made without departing from the spirit of the invention.

What I claim is:

l. A pilot bearing comprising two relatively rotatable concentric sleeves forming an annular cone ring with its rollers is then put in place within the bearing cup and the second disc 28 is placed in engagement with the outer edges of the cone ring. The bearing members are then clamped in place by means of the threaded collar I5 which is exteriorly cylindrical and which may be provided with suitable wrench receiving sockets 38 in its outer end. The outer sleeve lI2 with the sealing ring 32 mounted therein is then slipped in place over the bearing cup 2| until its shoulder I4 engages the cup and the ange 38 and sealing ring 32 closely overlie the cylindrical periphery of the collar I5 which with the the ange 30 and ring 32 close an end of the lubricant retaining bearing chamber. 'The closure member I8 is then screwed into the threaded end of the outer sleeve I2 to close the opposite end of the bearing chamber.

In Fig. 4 of the drawings the pilot bushing B is illustrated. This bushing is in most respects identical with the bushing shown in Fig. 2 and corresponding parts are designated by the same reference numerals with the addition of the letter a. In this modification the outer sleeve IZa is provided at one end with a peripheral outwardly projecting flange 40 and a closure member I8a is provided with a ange 4I that fits against chamber between them, the outer sleeve having an internal shoulder and the internal sleeve having an external shoulder, said shoulders being adjacent opposite ends of the chamber, an end closure member attached to the end of the outer sleeve opposite that having the internal shoulder, an end closure member attached to the opposite end of the inner sleeve, a double cone cup clamped between the shoulder and closure member of the outer sleeve, two cone rings and an intermediate spacer clamped between the shoulder and closure member 0f the inner sleeve, bearing rollers interposed between the cone rings and cup, and oil seals interposed between each closure member and the sleeve which rotates relative to the closure member.

2. A pilot bearing comprising two relatively rotatable concentric sleeves forming an annular chamber between them, the outer sleeve having an internal shoulder and the internal sleeve having an external shoulder, said shoulders being adjacent opposite ends of the chamber, a double cone bearing cup tting within the outer sleeve, means carried by the outer sleeve for clamping said cup to said internal shoulder, two cone rings and an intermediate spacer slidably tting on the inner sleeve, rollers interposed between said cone rings and cup, a collar screwed upon the inner sleeve, a lubricant retaining disc clamped between one of said cone rings and said external shoulder, a second lubricant retaining ring clamped between the oth'er cone ring and 'said collar, and oil seals at the ends of the annular chamber outwardly of said lubricant retaining discs.

3. A pilot bearing comprising two relatively rotatable concentric sleeves forming an annular chamber between them, the outer sleeve having an internal shoulder and the internal sleeve having an external shoulder, said shoulders being adjacent opposite ends of the chamber, a double cone bearing cup tting within the outer sleeve, means carried by the outer sleeve for clamping said cup to said internal shoulder, two cone rings and an intermediate spacer slidably fitting on the inner sleeve, rollers interposed between said cone rings and cup, a collar screwed upon the inner sleeve, a lubricant retaining disc clamped between one of said cone rings and said external shoulder, a second lubricant retaining ring clamped between the other cone ring and said collar, said retaining discs having their peripheries closely adjacent the interior of the outer sleeve, and inwardly projecting portions at the ends of said outer sleeve closely adjacent the outer faces of said discs to impede passage of lubricant.

4. A pilot bearing comprising two relatively rotatable concentric sleeves forming an annular chamber between them, the outer sleeve having an internal sh'oulder and the internal sleeve having an external shoulder, said shoulders being adjacentbpposite ends of the chamber, a double cone bearing cup tting within the outer sleeve and engaging said shoulder, a pair of cone rings tting on the inner sleeve, conical bearing rollers interposed between each cone and said cup, a collar threaded on said inner sleeve at the end opposite said external shoulder, a, lubricant retaining disc clamped between one of said cone rings and said collar, a second lubricant retaining disc clamped between said external shoulder and the other of said cone rings, said lubricant retaining discs having peripheries closely adjacent the interior of the outer sleeve, an inwardly projecting flange on the outer sleeve closely overlying the outer face of the disc engaged by said collar, a closure member attached to the outer sleeve, said closure member having a portion within the outer sleeve in clamping engagement with said cup and a portion closely overlying the outer face of said second lubricant retaining disc, an oil seal between said outer sleeve and collar outwardly of said inwardly projecting ange, and an oil seal between said closure member and the inner sleeve outwardly of said second lubricant retaining disc.

JOHN G. JERGENS. 

